1. Field of Invention
The present invention relates to refrigerant systems and hermetic compressors therefor, and in particular to the prevention of the complete loss of the refrigerant gas charge therein, to the ambient environment consequent to a refrigerant leak.
2. Description of the Related Art
Although it is well-known that a refrigerant system leak can develop, for example, at the compressor""s terminal assembly, or the seals between components, very few prior art compressors or refrigeration systems include a means for retaining the refrigerant gas should a leak occur. Rather, past approaches have focused primarily on attempting to prevent or minimize the likelihood of a leak. Prior attempts at retaining leaked refrigerant gas include the use of a recovery line and tank attached to a pressure relief valve (U.S. Pat. No. 5,408,840), a trap and diversion valve system (U.S. Pat. No. 5,564,280), or the use of rupture disks in communication with containment vessels (U.S. Pat. No. 5,379,604, U.S. Pat. No. 5,542,261, U.S. Pat. No. 5,761,261); the leak must occur through these devices for the leaked gas to be captured.
Recent regulations have forced a change from the chlorofluorocarbon (CFC) refrigerants, such as Freon(copyright), to hydrofluorocarbon (HFC) refrigerants that result in less ozone layer depletion in the event of a leak, thereby reducing potential damage to the environment. However, the HFC""s are still potentially harmful and should still be prevented from entering the atmosphere. Thus, if there is a system leak, retention of at least a portion of the leaking refrigerant gas, whether CFC or HFC, is necessary to best protect the environment.
An additional concern with leaking refrigerant is the cost of replacing same. Refrigerant is an expensive component of a refrigeration system; the cost of replacing even a portion of the system""s refrigerant can be considerable. Therefore, where at least a portion of the system""s refrigerant could be retained for reprocessing or reuse, rather than lost to the atmosphere, would be desirable.
A means for retaining at least a portion of the refrigerant which would otherwise leak from a refrigeration system, and allows the retained refrigerant to be recovered for later use, is therefore desirable.
The present invention provides a refrigeration system including a pair of heat exchangers, a hermetic compressor assembly having a compressor housing containing refrigerant fluid, fluid conveying lines and a flow restriction device forming a working refrigerant system, an evacuation volume having one of a first, substantially evacuated state and a second, fluid-containing state, a control valve located between the working refrigeration system and the evacuation volume and having an initial, closed position and an open position, and at least one refrigerant gas detector located externally of the working refrigeration system and in communication with the control valve. The evacuation volume is fluidly isolated from the working refrigeration system in the valve closed position and in fluid communication with the working refrigeration system in the valve open position. The valve is opened in response to refrigerant gas being detected by the detector, and refrigerant fluid in the working refrigeration system is sucked into the evacuation volume with the evacuation volume undergoing a change from its first to its second state and the valve resuming its said closed position when the evacuation volume is in the second state.
The present invention further provides a refrigeration system including a working refrigeration system including a hermetic compressor assembly having a compressor housing containing refrigerant fluid, a pair of heat exchangers, a flow restriction device, and fluid conveying lines, an evacuation volume located externally of the compressor housing and having one of a first, substantially evacuated state and a second, fluid-containing state, a control valve located between the working refrigeration system and the evacuation volume and having an open position and a closed position, and means for detecting a refrigerant leak external the working refrigeration system. The evacuation volume is fluidly isolated from the working refrigeration system in the valve closed position and in fluid communication with the working refrigeration system in the valve open position. The valve is opened in response to detection of a refrigerant leak and is subsequently closed to maintain the evacuation volume in its second state and fluidly isolated from the rest of the working refrigeration system.
The present invention provides a method of retaining at least a portion of refrigerant fluid of a refrigeration system in the event of a refrigeration leak therefrom, including detecting a refrigerant leak from the system, opening a valve located between the refrigeration system and an initially empty evacuation chamber in response to detection of the leak, receiving at least a portion of the refrigerant fluid in the system through the open valve and into the evacuation chamber, and closing the valve after the evacuation chamber has received refrigerant fluid from the system. Refrigerant which enters the evacuation volume may be received from, for example, the compressor housing.
The present invention also provides a hermetic compressor assembly including a compressor housing containing refrigerant fluid, a compressor mechanism located in the housing, a motor assembly located in the housing and operatively coupled to the compressor mechanism, an evacuation volume attached to and located externally of the compressor housing and having one of a first, substantially evacuated state and a second, fluid-containing state, a control valve located between said compressor housing and said evacuation volume and having an open position and a closed position, and at least one refrigerant gas detector located externally of said compressor housing and in communication with said control valve. The evacuation volume is fluidly isolated from the compressor housing in the valve closed position and in fluid communication with the compressor housing in the valve open position. The valve is opened in response to refrigerant gas being detected by the detector, whereby refrigerant fluid in the compressor housing is sucked into the evacuation volume and the evacuation volume undergoes a change from its first to its second state with the valve being in its closed position when the evacuation volume is in its second state.
An advantage of the inventive evacuation volume is that a portion of the refrigerant gas leaking from the system is sealably retained in a chamber so that that portion of gas does not escape to the ambient environment. The captured refrigerant may subsequently be recovered from the chamber for reuse.